Alkahest Bombs + Discoveries that alter bomb dice

[RainyDayNinja]

So I'm using a Crypt Breaker alchemist in PFS, and I'm wondering how his bomb damage will interact with discoveries that would change it. The Crypt Breaker has special "Alkahest Bombs" like so:

Alkahest Bombs wrote:

A crypt breaker’s bombs are specially designed to work best against constructs and corporeal undead—two foes commonly encountered in ancient tombs. Known as alkahest bombs, these bombs deal acid damage instead of fire damage. Alkahest is an alchemical fluid that eats away unliving flesh and animated constructs, but it doesn’t work as well against other targets. Against constructs and corporeal undead, alkahest bombs deal 1d8 points of damage, plus 1d8 points of damage for every odd-numbered level instead of 1d6. Against all other creatures, alkahest bombs deal 1d4 points of damage, plus 1d4 points of acid damage for every odd-numbered level.

Unlike other archetypes, which specify that the damage die goes down by a step (d6 becomes d4, d4 becomes d3, and so on), the Crypt Breaker just says they are d4s or d8s. So if I take a discovery such as Concussive Bombs ("Concussive bombs deal 1d4 points of sonic damage, plus 1d4 points of sonic damage for every odd-numbered level, instead of 1d6"), do I use d4s for all targets?

[CrackedOzy]

You could look at it two ways:

1) The implication of the Alkahest bombs feature is that you go up a die type against constructs & corporeal undead and down a die type against everyone else. So with concussive alkahest bombs you'd deal 1d6 sonic against constructs & corporeal undead and d3 against everyone else.

2) Alkahest bombs are just another variant, so using a variant bomb uses the variant's rules with no concern for the Alkahest rules. So your concussive bombs would do d4 versus everyone.

Personally I'm inclined to lean towards option #2.

[RainyDayNinja]

That's what I would guess too, but it seems odd that I could take the Acid Bombs discovery, and upgrade my bombs from d4s to d6s, plus damage over time, while keeping the same damage type...

[Skylancer4]

Option 2 is only 'valid' if you have the choice of using the archetypes bombs and the regular bombs. If the archetypes bombs replace the normal bombs you have to work with the alkahest bomb as a base damage in situations where damage dice are stated to go up or down.

[Skysalmon]

The wording for the alternative bombs in discoveries say that those bombs deal 1d4, not that their damage die is reduced down to 1d4. Using an alternative bomb typically does not utilize the rules of an Alkahest Bomb. You no longer apply the d8/d4 target priority variation, it's 1d4 across the board for whichever target in the case of Concussive Bomb discovery.
And Acid Bomb discovery's saying that you can "choose to have it inflict acid damage" is in reference to when you chose to use the Acid Bomb discovery. Using it is the choice to apply both acid damage and the extra 1d6 the following round.
In the case of using Acid Bomb discovery with Alkahest Bombs, the Alkahest Bomb d8/d4 target priority rules remain because it did not alter the damage die. So it would effectively be the d8/d4 acid damage + 1d6 acid damage 1 round later.